TREND program

• 2008-2013: establish possibility of automous radio-detection of EAS.

• 2008-2009: 6 antennas to define DAQ and analysis algorithm• 2010: 15 antennas + 3 scintillators, first EAS candidates• 2011-2013: 50 antennas, large statistics.

EAS signal Background

Ex: signal pattern:

Data treatment: elm background point sources

• Distinct features compared to EAS radio signals.→ Localized background can be rejected through data processing.

Shower axis

TREND-50 results• 2012: analysis of 320 live days with E-W polar. 323 EAS radio candidates selected.

Arrival direction distribution follows what is expected from EAS events. (to be confirmed with MC simulation… in progress)

Geosynchrotron intensity map(analytical treatment)…To be confirmed by simulation. In progress.

TREND-50 results• 2013: antennas rotated to N-S polar.• Analysis of 3 months of data: 11 candidates. So far so good. Full

dataset (+6 months) needed for final confirmation.

Confident that autonomous radio-detection of standard EASis possible with limited background contamination.

TREND 2008-2013

- Setup for (almost) free thanks to 21CMA.- Limited ressources and expertise on the radio technics.

- Focus on a single well defined objective: run radio array in standalone mode for EAS detcetion.

- Goal achieved (to be confirmed & published), thanks to high trigger rate & dedicated candidate selection algorithm.

TREND program

• 2008-2013: establish possibility of automous radio-detection of EAS.

• 2008-2009: 6 antennas to define DAQ and analysis algorithm• 2010: 15 antennas + 3 scintillators, first EAS candidates• 2011-2013: 50 antennas, large statistics.

• 2014-2015:preparatory phase for a GIANT array dedicated to INCLINED showers.

GRAND sensitivity

(threshold 3 1016eV)

(threshold 3 1017eV)

GRAND could reach similar (up to 2x better) sensitivity compared to Antartica projects.Angular resolution better than 0.1°.

To be confirmed/optimized with full MC.

PRELIMIN

ARY

TREND 2013-2015

• Optimise background rejection, in particular for inclined showers (linked to neutrinos).

• Tool:– Ground patern – Polarisation (?):EAS signal linearly polarized & perpendicular to direction of origin and Bgeo (at 1st order).

• 1st results expected summer 2015!!! (CNRS request)

GRAND-proto

• Polarization measurement– Dual arm ‘Butterfly’

antennas developped for CODALEMA & AUGER

– Upgrade to 3-arm antennas by TREND to retrieve full polar info (Xi’An XiDian University)

– Will be tested on site next week. Butterfly antenna @ AUGER

3-polar antenna prototype in test @ Xi’An

GRAND prototype• Prototype array of 30 antennas ( ) + 21 scintillators ( ) – Principle of EAS selection: For all events detected:

• Measure polarization on all triggering antennas• Select events with polarization pattern compatible

with EAS.• Offline cross-check with scintillator data.

– Allows a quantitative evaluation of the EAS selection procedure.

– Array along 21CMA North-South baseline (fibers for signal transmission)

– Offline cross-check reliable ONLY if e(ground array)=100% ! Requires precise simulations!

Electronic prototype test

2 antennas arms

Early amplification

Fiber to DAQLin HaiChuan

Front-end trigger + digitization

TREND signals @ 1GHz!

Fast front-end digitization (1GHz+12bits) developped by IHEP (Liu ZhenAn trigger Lab) & tested succesfully on site early March.

Technically very chalenging & too expensive!

Electronique GRAND-proto

• Alternative under study: power detector (integrating circuit) + slow numerisation (100MSPS)

Filter 20-200MHz

~15dB

Power detector

ADC 100MSPS

Analog card

Active antenna

FPGA

x3

Comparateur

Threshold

x3

DAQ

fibee

GPS

Timing

Analog trigger

BACKUP

Trigger principle / Buffer analysisT0:On each machine uNANT (NANT in 101-158):

– For every new buffer, compute snoise over 1024 samples of 1st sub-buffer.

– If sample i with amplitude Ai > N x snoise , trigger of level T0 on this antenna. 6<N<10.

T1:If at least 4 antennas have T0 triggers within a causal time window (Dt<DL/c), then data is sent to disk on machine u183 for all antennas with T0s

– to data file R[NRUN]_A[NANT]_data.bin: 1024 samples centered on sample i

– to time file R[NRUN]_A[NANT]_time.bin : • UNIX second of sample i• Buffer index of sample i• Subbuffer index of sample i• Position of sample i in subbuffer.

5

snoise

N x snoise

Code in C with MPI for Master/Slaves dialogs. Master program in python. Securities to check computer & ADC card status, buffer status, machines dropping out of DAQ. Monitoring tools to check status.

TREND acquisition chain

Filter 50-200MHz

LNA 24dB

40dBFilter 50-100MHz

Optical transmitter

buffer 200MB

disk

antenna

~100m coax cable

<4km fiber Optical recevier

ADC 8b 200MS/s

Electronic boardPod

DAQ room

TREND acquisition chain

fiber to the DAQ room

(<4km)

64dB ampli+ 50-100MHz

filter

Optical receiver

Antenna 101

U183300G disk

Triggered events Data file

u101

Time fileu101

scans ADC

8bits200

MS/s

Circular buffer

200MB

Circular buffer

200MBcomputeru101

CPU(trigger)

64dB ampli+ 50-100MHz

filter

Optical receiver

Antenna 158

Triggered events Data fileu158

Time fileu158

scans ADC

8bits200

MS/s

Circular buffer

200MB

Circular buffer

200MBcomputeru158

CPU(trigger)

50 parallel & identical chains

Optical fiber100m<d<4km

1 triggered event = 4 words in time file &

1024 samples in data file

DAQ room

computeru203

(ADCs init)

start signal

50 parallel & identical chains

Background discriminationEAS radio signals features:- Focused signal spot on ground (decreasing

when moving away from shower axis)- ~ Flat wavefront- Short (<500ns) pulses- Isolated pulses- Random in time- Random in direction- Come from the sky- Polarized ( shower direction & Bgeo)- Frequency signature (?)

Background radio signals features- If distant: ~constant amplitude

- If close: curved wavefront - Usualy long pulses- Usually repetition- Possible pattern for consecutive triggers (50Hz)- Point sources or trajectories- Mostly from ground- Non polarized- Frequency signature possible…

EAS and background have distinct features → data processing written to efficiently select candidates & reject background

TREND candidate selection procedure

10 ms power line

• Rejection of event bursts • Rejection of events with neighbours

• Rejection of waveforms with bad shape • Rejection of radius of curvature<500m• Rejection of events with Amax/Amin<1.5• Rejection of events with ‘holes’ in the

trigger pattern.• Info on direction of arrival hidden

during selection process.

TREND-15 setup (2010)• 15 log-periodic antennas + 3 particle detectors.

400 m

800

m

Ardouin et al., Astropart. Phys 34, 2011 <arXiv:1007.4359>

First EAS identification with autonomous radio

array

Nants θradio θscints ϕradio ϕscints

4 61±3 67±5 359±2 3±4

4 52±1 49±3 195±2 191±4

5 42±1 36±3 55±4 56±5

4 45±1 49±3 12±1 10±5

7 56±2 53±4 323±2 331±5

Some radio EAS candidates are coincident with scintillator coincidences + direction recons match!

Selection of radio EAS candidates with dedicated algorithm

Radio data(subset)

Reconstruction of 3-fold scintillator coincidences EAS

Scintillator data

• Independant trigger & analysis of scint data (EAS) & radio data (EAS radio candidates).

The TREND-50 setup• 50 antennas deployed in summer-automn 2010, total surface ~1.5km².• Stable operation since January 2011.• Goal: acquire large(r) stat of EAS. Quantify background rejection.

TREND-50~1.5 km²

TREND-15(2010)

Giant Radio Array for Neutrino Detection: how realistic is a 100kAntennas array ?

• Manageable if minimal amount of info delivered by antenna (16 bits per trigger, T0: 1kHz/antenna, T1: <1Hz/antenna => 200kB/s)• Affordable if unit price < 500 €.

P. Lautridou 2011